Tour T1 is an office skyscraper in La Défense, the high-rise business district west of Paris, France.Construction began in 2005 and the tower was completed and opened in 2008. The tower, 185 m tall, is the third-tallest skyscraper in La Défense after the Tour Total and Tour First . Since 2010, the entirety of the building's office space has been rented by GDF Suez.